One example of known waterproof connectors is shown in FIG. 8. In assembling waterproof connector 1, male housing 4, containing unillustrated male terminal fittings, is fixed in mount hole 3 in panel 2 by an unillustrated mounting device so that the opening of receptacle 5 of male housing 4 corresponds to mount hole 3. Female housing 6, containing unillustrated female terminal fittings, is partially inserted into receptacle 5 through mount hole 3 from the side of panel 2 opposite male housing 4. At this stage, bolt 7, mounted on female housing 6, engages the internal threads of an unillustrated nut mounted on male housing 4. Tightening bolt 7 causes housing 6 to move closer to male housing 4, thereby engaging the male and female terminal fittings.
Seal member 8 is mounted on female housing 6 to prevent entry of water from female housing 6 to male housing 4 through mount hole 3 of panel 2. When housings 4 and 6 are brought into the desired assembled state, seal member 8 comes into close contact with the surface of panel 2 while undergoing elastic deformation. As a result, water entering between female housing 6 and mount hole 3 is generally prevented from further entering male housing 4.
When housings 4 and 6 are drawn closer to each other by tightening bolt 7 which cooperates with the nut (not shown), a force is generated which resists the approach of the radially inner portions of the housings. Accordingly, a portion of female housing 6 in the vicinity of bolt 7 is forcibly moved toward male housing 4 when bolt 7 is tightened. However, a bending moment greater than the rigidity of female housing 6 is created thereby and acts most strongly on the portions of housing 6 which are distant from bolt 7, thereby elastically deforming them. Therefore, female housing 6 becomes curved so that it is spaced further from panel 2 as it extends farther from bolt 7. Thus, the sealing force acting between seal member 8 and panel 2 becomes weaker in these areas. As a result, the ability of seal member 8 to prevent entry of water becomes impaired due to the foregoing nonuniformity. Hence, water is more likely to leak into the housings in these areas.
A method disclosed in Japanese Unexamined Utility Model Publication 4/69874 has been suggested to solve the foregoing problem. Specifically, four bolts are mounted at the respective corners of a terminal fitting mounting area. The bolts are turned together by a gear mechanism so that the entire housing is forcibly and uniformly moved closer to the mating housing. However, according to this method, the use of an increased number of bolts and the requirement of the gear mechanism lead not only to a larger size housing, but also to increased production costs due to the more complicated construction. This problem is found not only in waterproof connectors of the panel type, but also in waterproof connectors in which a seal member is directly mounted between a male housing and a female housing.